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(N0 Model.)

L. J.'BAKBR.

BIT STOK. No. 250,186. Patented No'vj. 29,1881.-

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UNITED STATES PATENT OEErcE.

LORING J. BAKER, OF BOSTON, MASSACHUSETTS, ASSIGNOR TO FRANKLIN P, BAKER, OF SAME PLAGE.

BIT-STOCK.

SPECIFICATION forming part of Letters Patent No. 250,186, dated November 29, 1881.

Application led August 20, 1881. (No model.)

To all whom it may concern Be it known that I, LoRiNe J. BAKER, a citizen of the United States, residing at Boston, in the county of Su'olk and State of Massach usetts, have invented certain new and useful Improvements in Interchangeable Bit and Drill Stocks; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others Io skilled in theartto which it appertains to make and use the same, reference being had to the accompanying drawings, and to letters or tigures ot' reference marked thereon, which form a part of this specification. My present invention relates to compound bit-stocks and multiplying` hand-drills-that is, an implement capable of performing either of these functions and interchangeable from one to the other, as occasion requires; and it consists in the employmen t,'in combination with an ordinary bit-stock, of an arbor susceptible of free rotary motion in the head of the stock carrying at its outer end the drill or bit chuck, and at its inner end a toothed pinionv which engages and isvdriven by a spur-gear mounted loosely upon the handle ofthe stock, said gear being provided with a set-screw by which it may be confined rigidly to the stock when a carpenters bit is to be used, and the whole being so arranged that when the bitstock is in use and the gear is free to rotate about the handle of such stock the gear actuates the pinion to rotate the drillchuck with anincreased ormu'ltiplied movement, but when the gear is locked to the stock it rotates with it and has no eiiect upon the pinion and chuck and the implement becomes a simple bit-stock.

The drawings accompanying this specification represent, in Figure l, a longitudinal section of an implement containing my improvements. Fig. 2 is an end elevation; and Fig. Srepresents a modified construction ofthe handle of the stock.

In these drawings, A represents the body or frame of an ordinary carpenters bit-stock, the tubular head of the stock which supports the bit or drill arbor being shown at B,the handle of such stock at'C, its swiveled bearing-plate at D, and its lateral arms at a. and b.

45o In carrying out my invention I employ a straight arbor or spindle which is deposited in the bore of the head B, so as to rotate freely in the latter, and carries at its outer end a chuck,

E, for holding the drills or bits, while at its inner end, and inside of the arm a of the stock, this arbor C' has affixed to ita toothed pinion, F, which engages aspur-gear, G, loosely mounted upon the handle C of the stock, at the front end of the latter. The arm a of the bit-stock is, for convenience ot' manufacture, 6o formed independent of the handle C, and secured to the latter in a proper manner, in lieu of being cast or forged integral With it.

A set-screw, H, is screwed through one of the arms of the gear G in order, when the instrument is to be used as a bit-stock, to intercept and grasp the arm a of the stock, and prevent the said gear from rotating upon the handle or actuating the pinion F, thereby estopping rotations of the gear and pinion upon 7o their axes and holding them fast to the stock.

In the present instance the hub c of the gear G is part and parcel of a loose handle, I, which incloses the handle C of the stock, but the said handle I may be independent of the said hub, as shown in Fig. 8, in which case the user ot' the instrument must grasp the head of the setscrew with his thumb in order to prevent slip movement between such handle and the said gear.

The hub c ofthe gear may be integral with the body ot' the latter, as shown in Fig. 3 of the drawings, or screwed to it, as shown in Fig. 1, or otherwise secured to it.

When the implement is to be used as a carpenters bit-stock the set-screw His advanced until it intercepts the arm a ot' the stock and clamps the gear G to such arm. Under these circumstancesineither the gear G nor pinion F can rotate upon its axis, but both are com- 9o pelled to remain stationary upon or with the stock, and practically constitute part of the latter,and no rotarymovement of the bitwithin or with respect to the stock takes place.

When the implement is to be used as a machinists multiplying hand-drill the set-screw is retracted and the gearGallowed to rotate upon the handle C of the stock. Under these circumstances a complete rotation of the handle C bodily, and with it the gear, effects notonly 10o multipled rotations of the pinion F and arbor C to the extent due tothe differential size of the said pinion and gear, but the rotation of the gear bodily with the handle C and about the pinion effects an additional rotation of such pinion and of the drill-chuck.

1. In combination, the head B, constituting a support to the arbor C', and having the arm or crank a, and Wrist-pin or handle C, the arbor C', pinion F, secured to such arbor, the gear Gr, mounted loosely upon the Wrist-pin or handle C, andthe set-screw Il, or its equivalent, screwing through the gear and adapted to intercept and grasp the arm or crank a, the Whole be- Witnesses H. E. Lonen, F. CURTIS. 

